Silicon Sealing - How?

29 Jun 2006
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United Kingdom
Would someone please explain the art of silicon sealing to me please.
I'm trying to make various seals in the kitchen and bathroom and have bought anti-mildew silicon.

The problems I have encountered are:
1. The edges of the sealant are thin and peel away when cleaned.
2. The anti-mildew formula collects mildew
3. It refuses to seal my bathtop and won't bond to the plastic sealing strip I got from the tiling shop.

HOw is it meant to be applied? I am just a measly electrician and need the help of an expert finisher ;)
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What make is the silicone??????????
Were the walls completely dust and oil free before you tried to silicone???????????
Erm.. it was one from screwfix and not the cheapest. Not sure now.
And the surfaces were brand new and dust and oil free.

The intention was more about the technique I should be using? Is there a way to ensure a good and lasting seal is made?
2. The anti-mildew formula collects mildew

Only if constantly damp, wipe up any spills including around the bath top.

The best way I've found is to cut nozzle at desired angle and size and pull the gun away from the starting point while presssing the nozzle against the application. I am also one of those who licks their finger and drags it along the bead afterwards, never had any problems; though I'm sure lots of pros will say this isn't the way to do it.
Make sure you have lots of tissue or kitchen roll handy.
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Dont put too much on - if you try to fill the gap or corner with the gun you will in fact have put too much on. Better to do two passes than one big one and end up with half of it on the finger you used to do the smoothing!
The only brand that I have found that does not "rip" at the edges is the dow cornings (aka geocell).

I always degrease surfaces with meths first.

To prevent the silicone from sticking to your finger use dilute washing up liquid.

I only do one pass with the gun but have to remind myself that I am not using mastic and to be light of hand when smoothing.
BTW use a gun that has an autostop eg the Cox guns with the black plastic insert in the release mechanism. Much tidier. Only a fiver

I have never had any mould problems with the dow corning sanitary sealant- it does cost a bit more though.

Although not best practice you can actually push the silicone into place (slightly) if you have wetted your fingers with washing up liquid first.

Always apply constant pressure when applying and smoothing. I have purchased proper smoothing tools in the past but have never used them.

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